I use it in combination with a Canon 580EX II with a Canon EF500 f/4 L IS USM version I.
This is a perfect combo.
The product fit very well the flash, and is solid.
I\'m very satisfied by this purchase...

When I received my Better Beamer flash extender and installed it for the first time I was amazed at how big it was and how much it added to the profile of my gear. It really stood out above my 300mm f2.8 lens which is covered by a LensCoat Raincoat when I'm out shooting wildlife. By adding the matching Better Beamer cover it helped to break up the appearance and be less obvious when I'm hiding in the brush. I highly recommend this for anyone shooting wildlife!..